In an illuminating device where a plurality of kinds of LEDs emitting light having different color temperatures is used as a light source, it is possible to make the color of light of LEDs as a whole correspond to a different color temperature by simultaneously lighting up the plurality of kinds of LEDs and mixing the light emitted from the LEDs.
Accordingly, it is possible to tone light through the change of the color of light of LEDs as a whole by changing a light emission ratio for each kind of the color of light emitted from an LED. Further, it is possible to control the light emitted from all LEDs by changing the total amount of light emitted from a plurality of kinds of LEDs having different color temperatures. Furthermore, a user may operate the above-mentioned control by a remote controller in hand.
Meanwhile, for the change of the amount of light emitted from an LED, current flowing in the LED is generally changed. Accordingly, it is possible to change a light emission ratio by changing a ratio between currents of the LEDs for each kind of the color of emitted light. Further, it is possible to change the amount of emitted light by changing the sum of values of the current for each kind of the color of emitted light.
Therefore, in order to perform toning and light control by a plurality of kinds of LEDs that emit light having different color temperatures, LEDs may be lit for each color temperature of emitted light by independent LED lighting circuits and the respective LED lighting circuits may be controlled in a coordinated manner by a control unit such as a microcomputer.